Nashor spawns on 15 min mark. Dunno what's his respawn time. And I AM NOT SURE, but I think respawn on small camps is 1-2 mins, and on glyph ones like 4-5. Dragon I think 8-10. But as I said, I am not sure at all.

Id like to know exact numbers 2, but i kno barrens timer after dead is
etiher 5 or 8 mins, dragon i think is arounds the same

also cba to argue, but im pretty sure the respawn on lizard and golem are logner than the duration of the
buff. i Play tristana alot and having lizards is majorly important, i always have to steal enemies after mine runs out. Naturally i dont have it talented, i mean, mayb its viable but i wudnt bother trying utility specced trist :P

i just tested it out a minute ago:
red lizard and blue golem spawn the first time at 1:55 and respawn 5 minutes after been killed (if u kill the small creeps too,ofc)
small creeps(wraith,wolvs,small golems) spawn first time at 1:40 and respawn 80 seconds after been killed

small creep camps spawn at 1:40, and respawn after 1:20
Blue and red buffs spawn at 1:55 and respawn after 5 minutes
Dragon respawns after 6 minutes
Baron respawns after 7 minutes

To put this into context, if you're jungling and follow the standard route (blue buff, wolves, wraiths, red, golems) then your blue buff will respawn at around the 7:20 mark, and the red around 9 minute mark. This can come in very handy if you are counter-jungling. Also, if you are duo laning, the enemy jungler will be at the double golems just after you reach level 3 and will be low on health (having just killed the lizard), making them vulnerable to a gank.